Wireless shunts with storage

ABSTRACT

Devices and methods useful for storing and retrieving information related to a medical device such as an implantable valve or an implantable sensor are disclosed. An implantable valve can include a valve housing adapted to receive fluid flow therethrough between a valve inlet and a valve outlet. A valve assembly can be disposed within the valve housing and adapted to control a rate of fluid flowing through the valve housing. The implantable valve can also include a radio frequency identification (RFID) tag associated with the valve housing, adapted to store data, and including an antenna for communicating stored data to an external reading device. The RFID tag can store data related to, for example, a patient, a pressure setting of the valve assembly, and/or pressure sensor disposed within the valve. The RFID tag can also store an identifier that identifies the implantable valve, a pressure sensor disposed in the valve housing, a patient associated with the implantable valve, and/or patient clinical history.

FIELD OF THE INVENTION

The present invention generally relates to devices and methods fornon-invasively storing and accessing data related to medical devices,and more particularly to non-invasively storing and accessing datarelated to shunts.

BACKGROUND

It is often desirable to be able to provide data about medical devicesand/or patients using them, particularly for implanted medical devices.By way of illustration, treatment of hydrocephalus can involveimplanting medical devices in a body, and a caregiver may need accessdata about the implanted device, the patient in which the device isimplanted, or data generated by the device. Hydrocephalus is aneurological condition that is caused by the abnormal accumulation ofCSF within the ventricles, or cavities, of the brain. CSF is a clear,colorless fluid that is primarily produced by the choroid plexus andsurrounds the brain and spinal cord. CSF constantly circulates throughthe ventricular system of the brain and is ultimately absorbed into thebloodstream. CSF aids in the protection of the brain and spinal cord.Because CSF keeps the brain and spinal cord buoyant, it acts as aprotective cushion or “shock absorber” to prevent injuries to thecentral nervous system.

Hydrocephalus, which affects children and adults, arises when the normaldrainage of CSF in the brain is blocked in some way. Such blockage canbe caused by a number of factors, including, for example, geneticpredisposition, intra-ventricular or intra-cranial hemorrhage,infections such as meningitis, head trauma, or the like. Blockage of theflow of CSF consequently creates an imbalance between the amount of CSFproduced by the choroid plexus and the rate at which CSF is absorbedinto the bloodstream, thereby increasing pressure on the brain, whichcauses the ventricles to enlarge.

Hydrocephalus is most often treated by surgically inserting a shuntsystem that diverts the flow of CSF from the ventricle to another areaof the body where the CSF can be absorbed as part of the circulatorysystem. Shunt systems come in a variety of models, and typically sharesimilar functional components. These components include a ventricularcatheter which is introduced through a burr hole in the skull andimplanted in the patient's ventricle, a drainage catheter that carriesthe CSF to its ultimate drainage site, and optionally a flow-controlmechanism, e.g., shunt valve, that regulates the one-way flow of CSFfrom the ventricle to the drainage site to maintain normal pressurewithin the ventricles.

As noted above, one problem encountered with the use of shunt systems isthe difficulty in accessing data related to a shunt system implanted ina patient. One current technique for accessing data involves recordingdata related to a shunt system in a patient's written medical file.While this technique is advantageous in that it centrally collectspatient data, the written medical file is not always accessible, forexample, if the patient has an emergency and is taken to a hospitalwithout access to the written medical file. Furthermore, trackinghistorical data using this technique can be cumbersome.

Accordingly, there remains a need for storing and accessing data relatedto implanted medical devices, and particularly shunt systems.

SUMMARY

In one embodiment, an implantable valve is provided. The implantablevalve can include a valve housing adapted to receive fluid flowtherethrough between a valve inlet and a valve outlet. A valve assemblycan be disposed within the valve housing and adapted to control a rateof fluid flowing through the valve housing. The implantable valve canalso include a radio frequency identification (RFID) tag disposed withinthe valve housing and adapted to store data. The RFID tag can include anantenna for communicating stored data to an external reading device. TheRFID tag can store data related to a patient. The RFID tag can alsostore an identifier that identifies the implantable valve, a pressuresensor disposed in the valve housing, and/or a patient associated withthe implantable valve. Furthermore, the radio frequency identificationtag can store a pressure setting of the valve assembly that controls therate of fluid flowing through the valve housing.

A wide array of variations are possible. In some embodiments, theimplantable valve can include a sensor disposed within the valve housingand adapted to measure a pressure of fluid flowing through the valvehousing. In some embodiments, the radio frequency identification tag canstore calibration data for calibrating pressure measured by the pressuresensor. In some embodiments, the radio frequency identification tag canbe disposed a distance apart from the sensor. Alternatively, the radiofrequency identification tag can be disposed proximate to any of thevalve inlet of the valve housing and the valve outlet of the valvehousing. In yet other embodiments, the radio frequency identificationtag can be disposed proximate to a reservoir formed in the valvehousing. In some embodiments, the RFID tag can be disposed by itself,without any pressure sensor.

In another embodiment, an implantable data storage system is providedwhich can have a pressure sensor adapted to measure a pressure of fluidin a housing. A radio frequency identification tag can be associatedwith the pressure sensor, and it can be adapted to store data relatedthereto. The RFID tag can also include an antenna for communicatingstored data to an external reading device. In some embodiments, thepressure sensor can be disposed in a valve that is adapted to receivefluid flow therethrough between a valve inlet and a valve outlet. Thepressure sensor can be disposed within the valve and the radio frequencyidentification tag can be associated with the valve. The radio frequencyidentification tag can be disposed in a body at a location remote fromthe pressure sensor or, in other embodiments, disposed within a housingof the pressure sensor. The radio frequency identification tag can storecalibration data for calibrating pressure measured by the pressuresensor and/or data related to a patient's medical history. If a secondsensor is also implanted (for example, a flow sensor or another pressuresensor), the radio frequency identification tag can be associated with asecond sensor and be adapted to store data related to the second sensoras well. The pressure sensor and the radio frequency identification tagcan be coated with a fluid-impermeable coating.

In other aspects, methods for storing and retrieving information relatedto an implantable valve are provided. In one embodiment, a method caninclude positioning a distal end of a ventricular catheter within aventricle. The method can further include coupling a proximal end of theventricular catheter to a valve inlet formed on an implantable valve andcoupling a valve outlet formed on the valve to a drainage catheter suchthat fluid flows from the ventricle through the valve to the drainagecatheter. The method can also include using an external reading deviceto obtain data telemetrically from a radio frequency identification tagdisposed in the valve, for example, by positioning the external readingdevice in proximity to the radio frequency identification tag. The radiofrequency identification tag can be adapted to store data related to thevalve. In other embodiments, obtaining data can include obtaining datarelated to calibration data for the pressure sensor, patient data,patient clinical history, identification data for the valve, and/oridentification data for a pressure sensor disposed within the valve.

In still other embodiments, the method can include adjusting a rate offluid flow from the inlet valve to the outlet valve. The method can alsoinclude programming the radio frequency identification tag with anexternal reading device. In some embodiments, the radio frequencyidentification tag can store a pressure measurement obtained by apressure sensor disposed within the valve. In other embodiments, themethod can also include communicating with the pressure sensor and theradio frequency identification tag at a same frequency, or differentfrequencies, using an external reading device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a top view of one exemplary embodiment of an implantablevalve;

FIG. 2 is an exploded view of a portion of the implantable valve shownin FIG. 1;

FIG. 3 is a top view of one exemplary embodiment of a pressure sensor;

FIG. 4 is a schematic view of one exemplary embodiment of an implantablevalve having an RFID tag disposed therein;

FIG. 5 is a schematic view of the valve shown in FIG. 4 with an RFID tagdisposed in an alternate location;

FIG. 6 is a schematic view of the valve shown in FIG. 4 with an RFID tagdisposed in yet another location;

FIG. 7 is a schematic view of another embodiment of an implantable valvehaving an RFID tag disposed therein;

FIG. 8 is a cross-sectional view of the implantable valve of FIG. 4implanted in a body and one exemplary embodiment of an external radiofrequency telemetry reading device disposed adjacent thereto outside thebody for reading a signal from the implantable valve; and

FIG. 9 is a perspective view of one exemplary embodiment of a radiofrequency telemetry reading device.

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices andmethods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope is defined solely by the claims. The features illustrated ordescribed in connection with one exemplary embodiment may be combinedwith the features of other embodiments. Such modifications andvariations are intended to be included within the scope of the presentapplication.

Generally, methods and devices for storing and accessing data related toan implantable medical device, such as an implantable valve, areprovided. The methods and devices are particularly useful in the contextof valves for monitoring intra-ventricular pressure. In someembodiments, they can allow data related to a pressure sensor (or, forexample, temperature or flow sensors) in an implantable valve to bestored on and retrievable from an implantable radio frequencyidentification (RFID) tag associated with a pressure sensor and/or animplantable valve, thereby providing convenient and reliable access todata related to the implantable valve. A person skilled in the art willappreciate that, while the methods and devices are described below inconnection with an implantable valve for controlling cerebrospinal fluidand an associated pressure sensor, this description is by way ofillustration only, and that the methods and devices can be used for avariety of medical procedures and in a variety of devices, includingother kinds of sensors and/or sensors that are not disposed withinvalves.

FIGS. 1 and 2 illustrate one exemplary embodiment of an implantablevalve 100 that includes a radio frequency identification (RFID) tag 114.The valve 100 can be used alone or in combination with a pressure sensorassembly 118 that has a pressure sensor 900 therein, and/or otherpressure sensor assemblies disposed upstream or downstream of the valve100. As shown the, RFID tag 114 can be disposed inside the valve 100,but in other embodiments, the RFID tag 114 can be disposed outside thevalve or any distance apart from the valve and/or the sensor 900. Inmany embodiments, the RFID tag 114 can be offset from the pressuresensor to facilitate communication. As will be explained in more detailbelow, the RFID tag 114 can store and communicate data which, forexample, can be related to, for example, the valve 100, the pressuresensor 900, and/or a patient.

While the implantable valve 100 can have virtually any configuration,and a variety of implantable valves known in the art can be used, asshown in FIG. 1 the implantable valve 100 has a valve housing 102 withproximal and distal ends 104 a, 104 b. The housing 102 can havevirtually any configuration, shape, and size, preferably one making thehousing 102 suitable for subcutaneous implantation. Fluid (e.g., CSF)can flow through the housing 102 from an inlet (fluid entry) port 106 atthe proximal end 104 a and out an outlet (fluid exit) port 110 at thedistal end 104 b. The location and size of the ports 106, 110 can vary,but in many embodiments they can be adapted to allow fluid to flowtherethrough and into and out of the housing 102. The proximal anddistal ends 104 a, 104 b of the valve 100 can each be open and adaptedto couple to another medical device, such as a catheter. The valvehousing 102 can contain a valve assembly 112 for controlling the flow offluid from the inlet port 106 to the outlet port 110, and a pressuresensor assembly 118 for measuring a pressure of the fluid flowingthrough the valve 100, as will be described in more detail below withrespect to FIG. 2. While the valve assembly 112 and the pressure sensorassembly 118 of the valve 100 are shown in-line with one another andwith the inlet port 106 and outlet port 110, and the pressure sensorassembly 118 is positioned upstream of the valve 100, the valve 100 canhave a variety of other configurations, and the valve assembly 112, thepressure sensor assembly 118, the inlet port 106, and the outlet port110 can be positioned at various locations relative to one another. Forexample, the inlet port 106 can extend at a right angle with respect tothe pressure sensor assembly 118 such that the inlet port 106 extends ina direction substantially transverse to a longitudinal axis of the valve100. The valve assembly 112 can also have a variety of configurations.By way of non-limiting example, exemplary valves are described in U.S.Pat. Nos. 3,886,948, 4,332,255, 4,387,715, 4,551,128, 4,595,390,4,615,691, 4,772,257, and 5,928,182, all of which are herebyincorporated by reference in their entireties.

As shown in FIG. 2, the pressure sensor assembly 118 can include thesensor 900, a sensor housing 902, a backing 904, and an RFID tag 114.The sensor housing 902 can have a variety of shapes and sizes, but inthe illustrated exemplary embodiment the sensor housing 902 has agenerally hemi-spherical or domed portion 910 that defines a reservoirtherein. The sensor housing 902 can also include an inlet tube 912 thatcouples to the inlet port 106 of the valve 100, and an outlet tube 914that couples to the outlet port 110 of the valve 100. When the sensorhousing 902 is mated to the backing 904, the reservoir chamber definedby the housing 902 is sealed, thereby allowing fluid to flow from theinlet port 106 of the valve 100, through the sensor housing 902, throughthe valve 906, and out the outlet port 110 in the valve 100. The sensorhousing 902 can also include a flange 916 formed around a base of thedomed portion 910 to allow the device to be secured to tissue. Forexample, the flange 916 can include one or more suture holes formedtherein for receiving suture to attach the flange 916 to tissue.

The pressure sensor 900, such as the exemplary pressure sensor 300 shownin FIG. 3, can be formed on a microchip which can be coupled to anantenna 117 for communicating a sensed pressure to an external device.The antenna 117 can have a substantially circular shape, and themicrochip sensor can be coupled to the antenna 117 which can, forexample, be in the form of a gold microcoil. The sensor 900 and the RFIDtag 114 can also each include a fluid-impermeable coating, as furtherdescribed below, to protect the sensor 900 and the RFID tag 114 fromfluid flowing through the sensor housing 902 or from other fluid. Thesize of sensor can vary, but in one exemplary embodiment the microchipsensor 900 has a size that is in the range of about 1 mm to 3 mm, andmore preferably that is about 2.5 mm². Exemplary embodiments of apressure sensor and antenna are described in more detail in U.S. Pat.No. 5,321,989, U.S. Pat. No. 5,431,057, EP Patent No. 1 312 302, and inco-pending, commonly assigned U.S. patent application Ser. No.10/907,665, entitled “Pressure Sensing Valve” by Mauge et al., filedApr. 11, 2005 (now published as U.S. Publication No. 2006-0211946 A1),all of which are hereby incorporated by reference.

In use, the sensor 900, which is disposed within the sensor housing 902,measures the pressure of fluid flowing through the sensor housing 902.In particular, the inlet port 106 of the valve 100 can be coupled to theventricular catheter 120 for receiving fluid flow from one or moreventricles, and the outlet port 110 can be coupled to a drainagecatheter 122. As fluid enters the sensor housing 902, the pressure ofthe fluid will apply a force to active sensor membranes formed on thesensor 900, thereby allowing the fluid pressure to be measured. Thesensed pressure can be communicated, via the antenna, to an externalreading device, as described further below. Performance of the sensormembranes can vary with factors such as temperature, its age, and itsmaintenance, and the membranes may need to be calibrated to correct forsuch variance. Calibration can vary from sensor to sensor. Calibrationinformation, such as calibration coefficients and drift compensationvalues particular to the sensor 900, can be stored in the RFID tag 114(as well as other kinds of information, which will be described in moredetail below). Stored calibration information can be read by an externaldevice, identified as associated with this particular sensor 900, andused to calibrate the sensor 900. An external reading device, e.g., aradio frequency (“RF”) reader, can inductively couple to the RFID tag114 and non-invasively communicate data for storage to the RFID tag 114and/or non-invasively receive stored data from the RFID tag 114.

As shown, the sensor 900 and the RFID tag 114 can be disposed in thesensor housing 902, although the location of the RFID tag 114 can varywidely. For example, in other embodiments the RFID tag 114 can be remotefrom the sensor 900 and valve 100, for example, disposed outside thehousing 902 or implanted in another area of the body. In manyembodiments, the sensor 900 and the RFID tag 114 can be physicallyseparate, without a physical link or connection (e.g., a mechanical,electrical, or communication link or connection) between them. Such anarrangement can allow for a flexible, independent design of, in thiscase, the sensor 900, valve 100, and RFID tag 114. For example, thevalve 100 may be limited in size, and the RFID tag 114 can be locatedoutside the valve 100 while the sensor 900 can be located within thevalve 100. As another example, a sensor having a microchip (as describedabove in connection with FIG. 3) can dedicate the microchip to sensorfunctionality, and accordingly retain a relatively small size, while aseparate RFID tag can provide storage related that sensor. In addition,in some embodiments the RFID tag can be “retrofitted” to previouslyimplanted medical devices, for example, which were implanted without anRFID tag and do not have its storage and communication abilities. Insome embodiments, even though the RFID tag and the pressure sensor, forexample, are physically separate from one another (as in FIGS. 5-7, forexample), their respective antennas can be located in proximity oradjacent to one another, so that both devices can be read with anexternal reading device in one location. The external reading device maycommunicate with each device using a different frequency, protocol,etc., as will be described in more detail below.

As shown in FIG. 2, the valve 100 (or other device in which the RFID tag114 is embedded, or associated with) can have features to protect theRFID tag 114. For example, as shown in FIG. 2 the sensor assembly 118 ofthe valve 100 can include a washer 908, which can be provided to seatthe sensor 900 and/or the RFID tag 114, such that the washer 908 and thesensor 900 and/or the RFID tag 114 are positioned against the backing904. The washer 908 can also be configured such that the sensor 900and/or the RFID tag 114 are sub-flush with the washer 908, for example,to protect the sensor 900 and the RFID tag 114 from potential damagewhen the domed portion 910 of the housing 902 is depressed. The sensorassembly 118 can also include a needle guard 906 for protecting thesensor 900 and the RFID tag 114. In particular, the needle guard 906 canprotect the sensor 900 and the RFID tag 114 from coming into contactwith the domed portion 910 of the housing 902 when the domed portion 910is depressed, as the needle guard 906 can be positioned between thesensor 900 and the domed portion 910. The needle guard 906 can also beprovided to protect the sensor 900 and the RFID tag 114 from a needlebeing inserted through the domed portion 910 of the sensor housing 902.While the shape of the needle guard 906 can vary, in an exemplaryembodiment, as shown, the needle guard 906 has a substantially planar,circular shape and it is adapted to be disposed between the domedportion 910 of the housing 902 and the sensor 900. The needle guard 906can, however, include an opening formed therein and positioned adjacentto the microchip sensor 900 to allow fluid flowing through the sensorhousing 902 to come into contact with the sensor 900. In an exemplaryembodiment, a flange or protective member 918 is disposed over theopening, without blocking the opening from fluid flow, to prevent a userfrom accidentally inserted a needle through the opening. Furtherinformation on these features can be found in U.S. Publication No.2006-0211946 A1, referenced above.

FIG. 4 is a schematic illustration of one embodiment of the implantablevalve 100 of FIGS. 1 and 2 showing one possible location of the RFID tag114 disposed within the housing 102. In this embodiment, the housing 102has a substantially linear configuration with a reservoir 108 having alarger area than ports 106, 110, which can be advantageous for checkingthe shunt's patency, tapping the CSF, to administer therapy, or to housepressure or flow sensors. As indicated by directional arrows, fluid(e.g., CSF) can flow through the inlet port 106, through the reservoir108, and out the outlet port 110. As shown, the RFID tag 114, forstoring data and for communicating stored data, is disposed in thesensor housing 902 that defines the reservoir 108.

As mentioned above, the RFID tag 114 can be disposed in a wide varietyof locations. For example, it can be disposed in the valve 100, disposedat a location proximate to the valve 100, or implanted at any otherlocation within the patient associated with the valve 100, including ata location remote from the valve 100. FIG. 5 shows another schematicembodiment of the valve 100 in which the RFID tag 114 is disposedproximate to the distal end 104 b of the valve 100. FIG. 6 shows analternate schematic embodiment of the valve 100 in which the RFID tag114 is disposed outside the valve 100, in this example embodimentproximate to the proximal end 104 a of the valve 100, although the RFIDtag 114 can be implanted any distance from the valve 100. FIG. 7illustrates yet another schematic embodiment of the valve 100 where theRFID tag 114 is disposed in an offset tag housing area 400 of thereservoir 108. It should be understood that the reservoir 108 can haveany size and shape, including a shape accommodating the RFID tag 114. Inthe embodiments shown in FIGS. 4-6, the reservoir 108 has asubstantially rectangular shape, while in the embodiment shown in FIG.7, the reservoir has a substantially circular shape at its proximal endand a substantially rectangular shape at its distal end. In otherembodiments, the RFID tag 114 can be non-implantable and can be embeddedor housed in a RFID bracelet, key fob, card, etc., to hold information,and issued or given to a patient.

The housing 102 can be formed from a variety of materials. In anexemplary embodiment, however, the housing 102 is formed from aflexible, biocompatible material. Suitable materials include, forexample, polymers such as silicones, polyethylene, and polyurethanes,all of which are known in the art. The housing 102 can also optionallybe formed from a radio-opaque material. A person skilled in the art willappreciate that the materials are not limited to those listed herein andthat a variety of other biocompatible materials having the appropriatephysical properties to enable the desired performance characteristicscan be used.

The valve 100 and/or the RFID tag 114 can also optionally include acoating 116 that is adapted to hermetically seal all or at least aportion of the valve 100, the RFID tag 114, and/or other components suchas a sensor, an antenna, a connector, etc. The coating 116 can beapplied to only a portion of the RFID tag 114 that could be exposed tofluid, or it can be applied to the RFID tag 114, and optionally thevalve 100. The RFID tag 114 and the valve 100 can be coated separatelywith different coatings or together in a single coating. In theembodiment shown in FIG. 4 in which the RFID tag 114 is disposed in thevalve 100, the RFID tag 114 is preferably pre-coated prior to couplingthe sensor assembly to the housing 102. Once coated, the RFID tag 114can be appropriately positioned. An adhesive or other mating techniquecan be used to affix the RFID tag 114 within the housing 102, such as inthe embodiment shown in FIG. 5, however, in some embodiments it can beuseful to allow the RFID tag 114 to be removed from the valve 100 ifnecessary.

Alternatively, the valve 100 can be coated after the RFID tag 114 isdisposed in the valve 100 or located elsewhere to form a protectivesheath over the RFID tag 114 and the housing 102. The ports 106, 110 canbe protected from any coating applied thereto, formed after the coatingis applied, or be cleared of any coating applied thereto to allow fluidto flow therethrough. In other embodiments, only certain components ofthe valve 100 can be coated. A person skilled in the art will appreciatethat a variety of other techniques can be used to seal the RFID tag 114and/or other components of the valve 100.

The material used to form the coating 116 can vary, and a variety oftechniques can be used to apply the coating. By way of non-limitingexample, suitable materials include polyurethane, silicone,solvent-based polymer solutions, and any other polymer that will adhereto the components to which it is applied to, and suitable techniques forapplying the coating include spray-coating or dip-coating.

Referring to FIGS. 4-8, the shape, technical specifications, and size ofthe RFID tag can vary widely (as can the RFID tag 114 of FIGS. 1 and 2).In many embodiments, a relatively small RFID tag can be used so as tominimize the footprint of the tag in the device, for example withdimensions in a range of about 5 mm to 10 mm, but in other embodiments,tags with dimensions of about 3 mm to 50 mm can be used and any size ispossible. The RFID tag 114 can be adapted to be in communication with anexternal device (e.g., by having an antenna) and to store data.

The RFID tag 114 can have any shape, such as elliptical, circular, orrectangular (including square), and can have virtually any size. TheRFID tag 114 can be an off-the-shelf component. The following table(Table 1) lists, by way of example only, available RFID tags suitablefor use with the devices and methods described herein. Passive as wellas semi-passive and active tags can be used, although semi-passive andactive tags sometimes are larger than passive tags because they canincorporate an internal battery, e.g., for power purposes.

TABLE 1 Frequency Tag Type 125 KHz 5-7 MHz 13.56 MHz 303/433 MHz 860-960MHz 2.45 GHz Passive ISO11784/5, ISO10536 (ISO15693) — ISO18000-6ISO18000-4 14223 ISO18000-2 iPico (ISO15693) Electronic IntellitagDF/iPX Product Code μ-chip (“EPC”) Class 0 MIFARE EPC Class 1 (ISO14443)Tag-IT EPC GEN II (ISO15693) ISO18000-3 Intellitag tolls (Title 21) rail(Association of American Railroads (“AAR”) S918) Semi- — — — — rail (AARS918) ISO18000-4 Passive Title 21 Alien BAP Active — — — Savi (American— ISO18000-4 National WhereNet Standards Institute (ANSI 371.1) (“ANSI”)371.2) ISO18000-7 RFCode

The RFID tag 114 can store and/or communicate various types of data. Thetypes of data stored can be selected by a user. As indicated above, thedata can be related to a valve or any other implanted device(s), apatient associated with the valve, the RFID tag, sensed or measuredvalues (including historical values), and/or characteristics of fluidflowing through the valve or valve assembly. Non-limiting examples ofdata related to the valve 100 (or other devices) can include date ofdevice manufacture, device type (e.g., fixed or programmable), deviceidentifier code, and device maintenance history. Non-limiting examplesof data related to a patient can include patient identification (e.g.,name, identifying code such as Social Security Number, age, etc.),medical history information (e.g., dates of previous doctorexamination(s), disease history, etc.), and date of valve implantation.Non-limiting examples of data related to the RFID tag 114 can includeavailable memory space, date of tag manufacture, date of tagimplantation, tag type, tag identifier code, and tag maintenancehistory. Non-limiting examples of data related to implanted sensors orsensed characteristics can include current pressure setting (e.g., arate of fluid flow through the valve assembly 112), previous pressuresetting(s), date(s) of programming/adjustments (if the valve 100 isprogrammable), calibration parameter(s), settings of previouscalibration parameter(s), dates of previous calibration parameter(s),reasons for modifying previous calibration parameter(s) (e.g., adversemedical reactions such as fever or headache), and drift compensationvalues. Also, information related to a pressure sensor, such as date ofimplantation, sensor type, sensor ID, values read, zeroing of thesensor, date of zeroing, specific pressure reading and date taken, canbe stored. Storing and communicating characteristic data such ascalibration parameters and drift compensation values can includepolynomial coefficients to calculate an actual pressure value from ameasured pressure value. The RFID tag 114 can store such data and allowan external RF reader to obtain a correct measurement from the valve 100without having to depend on external storage devices.

As illustrated in FIG. 8, the RFID tag 114 can be adapted to interactwith a wireless signal 500 from an external reading device, such as anRF telemetry device 502 (shown in more detail in FIG. 9). The readingdevice 502 can emit a signal 500 at one frequency or over a range offrequencies and can receive a response thereto, e.g., from the RFID tag114 or a sensor.

Virtually any type of external reading device can be used as the RFtelemetry device 502. In one exemplary embodiment, the RF telemetrydevice 502 can include an RF module (e.g., transmitter and receiver), acontrol unit (e.g., microcontroller), a coupling element to thetransponder (e.g., antenna), and an additional interface (e.g.,Recommended Standard (RS) 232, RS-485, Firewire, USB, Bluetooth, ZigBee,etc.) to enable communication with another external device (e.g., apersonal computer). The RF telemetry device 502 can provide the powerrequired by the RFID tag 114 to operate, e.g., through the couplingelement. The RF telemetry device 502, as shown in FIG. 8, can bepositioned adjacent to the RFID tag 114 to telemetrically communicatewith the RFID tag 114, and thereby obtain and/or transmit data. Furtherinformation on the use of such RFID tags, including techniques forinterrogating them and examples of them, can be obtained from U.S. Pat.Nos. 6,025,725, and 6,278,379, and U.S. Patent Application PublicationNo. 20040134991, all of which are hereby by incorporated by reference intheir entireties.

In some embodiments, multiple RFID tags and/or other devices (such asthe pressure sensor described above) capable of wireless communicationcan be implanted in a patient. Multiple RF telemetry devices can be usedto communicate with these devices. Alternatively, the RF telemetrydevice can provide the ability to communicate with multiple devices,using different frequencies, different communication protocols, and soon. For example, the same RF telemetry device 502 can obtain data fromboth the pressure sensor and the RFID tag, which as mentioned previouslycan have antennas located in proximity to one another to facilitate suchcommunication. In some embodiments, the RF telemetry device 502 can readidentification data, such as serial numbers, from the sensor and/or theRFID tag to identify from which device it is receiving data.

In other embodiments, the RFID tag 114 can store data related to not onebut a plurality of implanted medical devices, which may be devices thatwere implanted concurrently with the RFID tag 114 or those being“retrofitted” or “upgraded” with later implantation of an RFID tag. TheRF telemetry device 502 can read from the RFID tag identification data(and other data) for each of a plurality of implanted devices. The RFIDtag can store and output data so as to associate it with the implanteddevice to which it relates, for example via a table correlating deviceidentifiers with data values.

In another aspect, a method for obtaining data related to medicaldevice, such as the valve and/or pressure sensor of FIGS. 1-2, isprovided. The inlet port 106 of the valve 100 can be coupled to aproximal end of a ventricular catheter 120 that has had its distal endpositioned in a patient's ventricle. As shown in FIG. 8, the valve 100can be implanted in a patient, such as a patient's shoulder area, whilethe typically more flexible catheter can extend through the patient tothe ventricle. A drainage catheter 122 can be coupled to the outlet port110 of the valve 100, in which the drainage catheter can extend throughthe patient to an area where excess fluid can safely drain. The rate offluid flowing through the valve 100 from the inlet port 106 to theoutlet port 110 can be controlled by the valve assembly 112. Datarelated to the valve 100 can be obtained at an external reading device(e.g., using the RF telemetry device 502) from an antenna coupled to theRFID tag 114 that is associated with the valve 100.

In the embodiment shown in FIG. 8, the RFID tag 114 is disposed in avalve 100 implanted in a shoulder area of a patient (shown forsimplicity without catheters in communication with either of the ports106, 110). However, it should be understood that the valve can beimplanted virtually anywhere, for example subcutaneously behind the ear,or on the head, torso, etc. Further, as indicated above, the RFID tag114 can be disposed outside the valve 100, at a location proximate orremote to the valve 100. The method can include implanting the RFID tag114 concurrently or subsequently (e.g., as a replacement or retrofit)with the valve or other medical device.

In some embodiments, multiple pressure sensor assemblies can be used,each with an associated RFID tag, and the pressure sensor assemblies canbe disposed at various locations relative to one another, notnecessarily in a valve. The use of multiple pressure sensor assembliescan be particularly advantageous as it can allow a differential pressureof the system to be obtained. The differential pressure of the systemshould be equal to the operating pressure of the system, thus indicatingwhether the system is performing properly. CSF can flow from a patient'sventricle through a catheter (or other medical device) to the inlet port106 and through the valve 100. Thus, the pressure of fluid flowingthrough the reservoir 108 of the valve 100 can correlate to thepatient's ICP despite the valve's implantation at a location other thanthe patient's ventricle. Moreover, as indicated above, the RFID tag 114can be disposed outside the valve 100, at a location proximate or remoteto the valve 100.

Further information on wireless shunts can be obtained from U.S. patentapplication Ser. No. 11/931,041, entitled “Wireless Pressure SettingIndicator” by Salim Kassem, U.S. patent application Ser. No. 11/931,127,entitled “Wireless Flow Sensor” by Salim Kassem, and U.S. patentapplication Ser. No. 11/931,151, entitled “Wireless Pressure SensingShunts” by Salim Kassem, all of which are being filed on the same dateas the present application and which are hereby incorporated byreference in their entirety. Also incorporated by reference in itsentirety is co-pending, commonly assigned U.S. patent application Ser.No. 10/907,665, entitled “Pressure Sensing Valve” and published as U.S.Publication No. 2006-0211946 A1.

A person skilled in the art will appreciate that the various methods anddevices disclosed herein can be formed from a variety of materials.Moreover, particular components can be implantable and in suchembodiments the components can be formed from various biocompatiblematerials known in the art. Exemplary biocompatible materials include,by way of non-limiting example, composite plastic materials,biocompatible metals and alloys such as stainless steel, titanium,titanium alloys and cobalt-chromium alloys, glass, and any othermaterial that is biologically compatible and non-toxic to the humanbody.

One skilled in the art will appreciate further features and advantagesof the invention based on the above-described embodiments. Accordingly,the invention is not to be limited by what has been particularly shownand described, except as indicated by the appended claims. Allpublications and references cited herein are expressly incorporatedherein by reference in their entirety.

What is claimed is:
 1. An implantable system, comprising a firstimplantable device configured to be implanted in a patient; and a secondimplantable device configured to be implanted in the patient separatelyfrom the first implantable device such that the first implantable deviceand the second implantable device are both implanted in the patient, thesecond implantable device comprising a valve housing adapted to receivefluid flow therethrough between a valve inlet and a valve outlet, thevalve inlet and a valve outlet defining a longitudinal axis of the valvehousing; a valve assembly disposed within the valve housing along thelongitudinal axis and adapted to control a rate of fluid flowing throughthe valve housing; and a radio frequency identification (RFID) tagdisposed within the valve housing at a location laterally offset fromthe longitudinal axis, the RFID tag being adapted to store first datarelated to the first implantable device and to store second data relatedto the rate of fluid flowing through the valve housing, the RFID tagincluding an antenna for communicating the stored first and second datato an external reading device, and the RFID tag being adapted tocommunicate the stored first data uniquely relating the stored firstdata to the first implantable device and communicate the stored seconddata uniquely relating the stored second data related to the rate offluid flowing through the valve housing to the second implantabledevice.
 2. The implantable system of claim 1, further comprising asensor disposed within the valve housing along the longitudinal axis andadapted to measure a pressure of fluid flowing through the valvehousing.